indexPathForRow不會返回正確的值

我正在嘗試使用3D Touch，除了下面的功能，一切都很好，當滾動時我無法獲得正確的值indexPath和indexPathForRow(at: location)。此功能不能說用戶是否滾動表格，並且始終將用戶在應用中可以看到的第一行設置爲第一行。indexPathForRow不會返回正確的值

我的代碼：

func previewingContext(_ previewingContext: UIViewControllerPreviewing, viewControllerForLocation location: CGPoint) -> UIViewController? { 

     guard let indexPath = workoutTable?.indexPathForRow(at: location) else {return nil } 
     guard let cell = workoutTable?.cellForRow(at: indexPath) else {return nil } 
     guard let workoutDetailPeek = storyboard?.instantiateViewController(withIdentifier: "WorkoutDetailPeek") as? WorkoutDetailPeek else {print("else31"); return nil } 

     workoutDetailPeek.workoutId = "\(Int(workout[(indexPath as NSIndexPath).row].workoutId)!-2)" 
     workoutDetailPeek.preferredContentSize = CGSize(width: 400.0, height: 267.0) 
     previewingContext.sourceRect = cell.frame 
     return workoutDetailPeek 
}

我一直通過不同的3D觸控實現，但這個功能似乎每個人都工作正常，除了我。

來源

2016-12-26 ali farhangmehr